30 deg. difference in manifold temp?

[imported_DANA1]

hi all. i'm working on a 1997 mercruiser 5.7 alpha one freshwater cooled i/o should my exaust manifolds run at the same temp? measuring at top of manifold just past rubber cuppler on exit elbows there is a 27 to 30 degree difference. the port side being hottest at180 degree vs 150 on starbord side readings were taken with engine running on garden hose at 800 rpm. thanks

 

[DHPMARINE]

Re: 30 deg. difference in manifold temp?

Port is usually hotter due to circulation patterns,but I have never actually measured them,temperature wise. Can you hold your hand on the 150 side ?And does the portside just feel a bit warmer ?

DHP

 

[imported_DANA1]

Re: 30 deg. difference in manifold temp?

yep thats what made me curious. one feels warm the other just a little too warm to leave hand on for any length of time. thanks

 

[Haut Medoc]

Re: 30 deg. difference in manifold temp?

Fresh water cooled.....
Does this mean a closed system, or that you only run it in fresh , not salt water?

 

[imported_DANA1]

Re: 30 deg. difference in manifold temp?

closed cooling 1/2 system block only
http://i153.photobucket.com/albums/s225/alilditzie/P3040003.jpg
http://i153.photobucket.com/albums/s225/alilditzie/P3040002.jpg
http://i153.photobucket.com/albums/s225/alilditzie/P3040001.jpg
thanks again

 

[Haut Medoc]

Re: 30 deg. difference in manifold temp?

Well, for the price of a couple gaskets, I would investigate.......
How old are they & how much salt water use?
I would check the riser & extensions for any blockage from scale, especially where the coolant dumps into the elbows,.......
30 degrees is more than just a little bit, IMHO......

 

[bruceb58]

Re: 30 deg. difference in manifold temp?

Did you have the water on high enough?

When was the raw water impeller changed last?

Was your FWC installed when the engine was new or after some salt water use? Could have a blocked heat exchanger.

I would also do what Haut Medoc said to try.

 

[imported_DANA1]

Re: 30 deg. difference in manifold temp?

impeller is new checked heat exchanger looked suprizingly good for its age. i agree with you ill pull risers and inspect,just a good idea to be sure. thanks

 

[Bondo]

Re: 30 deg. difference in manifold temp?

While my Temp. Calibrated Palm isn't as accurate as my Torque calibrated Elbow,.......

I've Never seen a motor that the Risers were the Same temp.......

I don't really see a Problem,............

Go Boating,+ Have some Fun........